1. Field of the Disclosure
The present invention relates to a touch sensor in panel type liquid crystal display device (LCD), more particularly, to a driving circuit of a liquid crystal display device that is able to smoothly and gently connect coordinates not sensed by touch sensors smoothly by using a simple configuration and method.
2. Discussion of the Related Art
Liquid crystal display devices controls light transmissivity of a liquid crystal layer via an electric field applied to the liquid crystal layer according to a video signal to display images. Such a liquid crystal display device is a flat panel display device having an advantage of small thin type with low electricity consumption, which has been applied to various fields such as a portable computer, office automation apparatus, audio/video apparatus and the like. Especially, an active matrix type LCD device is advantageous in representing a moving picture because a switching device formed in every liquid crystal cell is actively controllable.
A thin file transistor (TFT) is commonly used as switching device for the active matrix type LCD device.
Recently, technology that a touch screen panel is attached to such the LCD device has been proposed. If a finger or touch pen is touched on a screen by a user, the LCD device having the touch screen panel attached thereto detects information on the touch position and embodies various applications based on the detected information. However, such the LCD device has disadvantages of cost increase because of the touch screen panel, yield decrease caused by the addition of the process attaching the touch screen panel to the liquid crystal display panel and brightness deterioration and thickness increase of the liquid crystal panel.
To solve the above problems, a touch-sensor-in-panel type LCD device has been proposed in various ways instead of the touch screen panel. The touch sensor in panel type LCD includes a touch sensor circuit including a sensor TFT formed in a pixel cell of the liquid crystal panel. Each of the pixel cells of such the touch sensor in panel type further includes a touch sensor circuit rather than a pixel circuit displaying an image. The touch sensor circuit senses a light from the outside and it supplies a light sensing signal corresponding to the light to a readout integrated circuit (IC).
However, the above touch sensor circuits have influence on an aperture ratio or formation section of each pixel cell and on full resolution of a liquid crystal panel as well. As a result, resolution of touch sensor circuits is formed lower than the full resolution of the liquid crystal panel. Then, coordinates extracted by the touch sensor circuits are not connected smoothly only to deteriorate user satisfaction. Because of that, the coordinates not sensed should be compensated by embodying a hardware configuration to be complex, for example, increase of sensing frequencies or usage of plurality of frame memories.